1. Field of the invention
The present invention relates to a developing roller and a process cartridge for use in an electrophotographic image forming apparatus, and an electrophotographic image forming apparatus.
2. Description of the Related Art
In Japanese Patent Application Laid-Open No. 2008-112150 (U.S. Pat. Publication No. 2008/0193172), a developing roller is described having a surface layer, which is formed around a mandrel and contains a urethane resin and urethane resin particles, and having a convex portion derived from the urethane resin particles on the surface.
Recently, a demand for forming a high quality electrophotographic image has further increased. Under the circumstance, a matter of concern is how faithfully an electrostatic latent image formed on an electrophotographic photosensitive member is developed. The present inventors have repeatedly conducted studies on a contact development apparatus using a developing roller described in Japanese Patent Application Laid-Open No. 2008-112150 (U.S. Pat. Publication. No. 2008/0193172). As a result, they found that toner is slightly scattered in a developing process of an electrostatic latent image formed on an electrophotographic photosensitive member. They recognized that such scattering of toner should be overcome in order to further improve the quality of an electrophotographic image.